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Poster De Conférence Année : 2020

Formulation of cold recycled asphalt mixtures: a microscopic scale study of bitumen emulsion wetting on virgin aggregates and reclaimed asphalt pavement (RAP)

Résumé

The cold recycling of bituminous materials recovered from pavements, also called Reclaimed Asphalt Pavement (RAP), presents both economic and environmental advantages. This technique allows the use of bitumen emulsion. At present, there is no rational formulation method for emulsion mixtures and their numerous applications in road pavement remain the expertise of constructors. Recycling with bitumen emulsion raises questions about the interactions of emulsion both with the virgin aggregates and RAP. These two types of materials have very different physicochemical properties. If current knowledge has enabled description of interactions between emulsion and virgin aggregates according to their physicochemical property, those with RAP, aggregates covered with aged binder, remain to be clearly determined. The adsorption process of surfactants on the RAP material, which conditions emulsion wetting and new binder adhesion, should be clarified according to its hydrophobic nature and low reactivity. The main objective of this study is to determine emulsion breaking mechanism on RAP, in comparison with virgin aggregates, whose physicochemical compositions were known. For this purpose, the experimental protocol consisted of conducting surface tension and contact angle measurements on six emulsions, varying the emulsifier nature and content, on polished substrates of diorite and granite and on aggregates coated with an aged binder film extracted from RAP which were exposed to traffic and environmental conditions for several years. The results showed an increase in the surface tensions of emulsions formulated, comparatively to those of aqueous phases from which they were prepared. However, a slight influence of emulsifier nature and content was observed between the surface tension values of the six emulsions tested. The contact angle values of emulsions with RAP are higher than those obtained with the virgin aggregates, whatever the emulsifier nature and content. This indicates the hydrophobic nature of RAP, even though the presence of water inside bitumen emulsions.
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Dates et versions

hal-03207943 , version 1 (26-04-2021)

Identifiants

  • HAL Id : hal-03207943 , version 1

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Yacouba Konaté, Florence Rouyer, Layella Ziyani, Anne Dony, Jean-Eric Poirier, et al.. Formulation of cold recycled asphalt mixtures: a microscopic scale study of bitumen emulsion wetting on virgin aggregates and reclaimed asphalt pavement (RAP). 10th International Colloids Conference 2020, Dec 2020, ONLINE, France. ⟨hal-03207943⟩
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